The widow of the late Palestinian leader has described the death of her husband, Yasser Arafat, as a 'political assassination' that constitutes 'the crime of the century'.

Suha Arafat was speaking in Doha on Thursday following a report by Swiss scientists, which revealed Arafat ingested lethal radioactive polonium before his death nine years ago, and had high levels of it in his body that could not have been accidental.

"It's a very sad feeling, as if I'm mourning my husband again, as if he died yesterday," she said.

"I can't predict who is behind this. We have done a judicial appeal in the French courts for (the) assassination. We have confidence in the French justice. We're waiting for (the) results."

Arafat died in November 2004 at a French military hospital, a month after falling violently ill at his Israeli-besieged West Bank compound.

At the time, French doctors said he died of a stroke and had a blood-clotting problem, but records were inconclusive about what caused that condition.

The Swiss scientists said that they found elevated traces of polonium-210 and lead in Arafat's remains that could not have occurred naturally, and that the timeframe of Arafat's illness and death was consistent with poisoning from ingesting polonium.

"Whoever did this crime is a coward because Yasser would have wanted always to die on the battlefield or died defending his people but he died on his bed, very weak," Suha said.

Israel has repeatedly denied a role in Arafat's death and did so again on Thursday.

Shortly after his death, the Palestinians launched their own investigation, questioning dozens of people in Arafat's compound, including staff, bodyguards and officials, but no suspects emerged.